Environmental allergies are reactions that occur when the immune system overreacts to substances in the environment, known as allergens. Common allergens include pollen from trees, grasses, and weeds, as well as mold spores, dust mites, and pet dander. These allergens can trigger symptoms such as sneezing, itching, and difficulty breathing. People with environmental allergies may experience seasonal symptoms, particularly during certain times of the year when pollen counts are high. Management strategies include avoiding allergens, using air purifiers, and taking medications like antihistamines. In some cases, allergy shots, or immunotherapy, may help reduce sensitivity to specific allergens.